In arc lamp and other high output bulbs, residual stress due to thermal creep is a key contributor to bulb breakage. Thermal creep is exacerbated at higher ultraviolet (UV) output power from arc lamps, either in the conventional DC discharge mode of operation or with laser sustained plasmas in lamps, due to the higher absorption of UV light in the glass which leads to increased operating temperatures.
Traditionally, bulbs rely on natural convection for cooling. Natural convection cooling results in a highly asymmetric temperature profile on the lamp. Also, the generally accepted operating lamp temperature limit of less than 750° C. is excessive and results in quick buildup of residual stress. A peak temperature of less than 600° C. would be more sustainable.
Consequently, it would be advantageous if an apparatus existed that is suitable for actively cooling high output bulbs to an operating temperature below 600° C.